Method for the elimination of erosion failures on the surfaces of high pressure-high temperature devices

ABSTRACT

A method of repairing erosion failures which comprises filling the site of erosion failure with powdered refractory metal consisting of nickel, iron, cobalt, manganese, molybdenum, titanium, tantalum, tungsten, chromium, niobium and rhenium taken either alone or in various combinations thereof, followed by subjecting said site to the effects of high temperature and high pressure, e.g. directly in the course of synthesizing artificial diamonds or other superhard materials, thereby sintering the powdered metal and eliminating the erosion failure.

United States Patent Baku] et al. Mar. 25, 1975 METHOD FOR THE ELIMINATION OF [51] Int. Cl. B22f 1/00, B22f 7/00, B22f 7/08 EROSION FAILURES ON THE SURFACES [58] Field of Search 75/208; 264/36; 425/78 OF HIGH PRESSURE-HlGH TEMPERATURE DEVICES [5 6] References Cited [76] Inventors: Valentin Nikolaevich Bakul, ulitsa UNITED STATES PATENTS Kimva 3411, 12; Alexei 3,202,732 8/1968 Braun ct al. 264/36 losifovich Prikhna, ulitsa vyshgorodskaya' 20; Primary Examiner-Carl D. Quarforth Alexandr Alexzlndmvlch Assistant Examiner-B. Hunt Shulzhenko, uhtsa Novo-Konstantinovskaya, l7, kv. 27; Alexandr F edorovich Lyashenko, [57] ABSTRACT ulitsa Vyshgorodskaya, 52, korpus A method of repairing erosion failures which com- 3, kv. 62; Vasily Ivanovich prises filling the site of erosion failure with powdered Zhitnetsky, ulitsa Vyshgorodskaya refractory metal consisting of nickel, iron, cobalt, 100/14, kv. 58, all of Kiev, U.S.S.R. manganese, molybdenum, titanium, tantalum, tung- [22} Filed: 16, 1973 sten, chromium, moblurn and rhemum taken either alone or in various combinations thereof, followed by [2! Appl. No.: 333,300 subjecting said site to the effects of high temperature and high pressure, e.g. directly in the course of synthe- Apphcanon Data sizing artificial diamonds or other superhard materials, cmtmulmmn'pan of 104501 thereby sintering the powdered metal and eliminating ahdndmed' the erosion failure.

[52] U.S. Cl 75/208 R, 264/36, 425/78 1 Claim, 2 Drawing Figures METHOD FOR THE ELIMINATION OF EROSION FAILURES ON THE SURFACES OF HIGH PRESSURE-HIGH TEMPERATURE DEVICES FIELD OF THE INVENTION This application is a Continuation-in-Part application of Ser. No. 104,303, now abandoned, filed Jan. 6, 1971.

This invention relates to high pressure-high temperature devices and, more particularly, to methods of eliminating erosion failures in said devices, which find application, for the most part, in the synthesis of artificial diamonds and cubic boron nitride.

DISCUSSION OF THE PRIOR ART A high pressure-high temperature device is known (see US. Pat. No. 2,941,243), which comprises two dies braced on the periphery thereof with strengthening rings and having recesses on the mating butt ends, with the recesses forming a cavity which accommodates a reaction vessel. In these recesses cylindrical hollows are made In order to minimize heat dissipation from the reaction vessel, and also with a view toward eliminating erosion wear during the course of operating the device under high pressure and temperature conditions, use is made of alumina or other suitable heatinsulating material for packing the hollows.

The prior art device is subject to drawbacks in that in the dies, which are manufactured from hard-metal alloys, provision is made for cylindrical hollows which are packed with heat-insulating material, the angle formed by the bottom and the wall of the hollow being the site of stress concentrations, thereby adversely affecting the strength characteristics and, hence, the service life of the die.

A further drawback of the prior art device is conccrned with the necessity of employing a special-type conducting disk in order to provide an electric circuit between the die of a high pressure device and the reaction chamber. Thus. in order to obviate this drawback, various known devices are designed so as to dispense with cylindrical hollows packed with a heat-insulating material (see US. Pat. No. 2,941,244), however, in this instance problems arise which are associated with the elimination of erosion failures.

SUMMARY OF THE INVENTION It is accordingly an object of the present invention to improve on the performance characteristics of high pressure'high temperature devices.

It is another object of the present invention to provide a simple and novel process for the elimination of erosion failures on the surface of hard-metal alloy or steel elements.

A further and more specific object of the present invention is to provide a method of restoring the working volume of high pressure-high temperature devices, which volumes change due to erosion wear during the course of operating the devices.

These and other objects are attained by the inventive method of eliminating erosion failures on the surfaces of elements of high pressure-high temperature devices intended for synthesis of man-made diamonds and other superhard materials wherein, according to the invention, an erosion wear site is filled with powdered refractory metal selected from the group consisting of nickel, iron. cobalt, manganese, molybdenum, titanium, tantalum, tungsten, chromium, niobium, and rhenium taken either singly or in various combinations thereof and thereafter subjected to the effect of pressure and temperature in the course of synthesizing artificial diamonds or other superhard materials.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustrated hereinbelow by a detailed description with reference to the accompanying drawings, wherein:

FIG. 1 illustrates a die subject to erosion wear; and

FIG. 2 is the die of FIG. 1 after elimination of the erosion wear.

DETAILED DESCRIPTION During the course of synthesizing artificial diamonds and other superhard materials in high pressure-high temperature devices, haard-metal alloy or steel dies of the devices undergo erosion wear, with the erosion wear phenomena resulting in working volume changes and diminution of the service life of the device. Working volume variations in high pressure-high temperature devices result in changes in the pressure produced in the dies at one end and the same force being applied thereto by presses, whereby deviations ensue from the working parameters (temperature, pressure) during the process of synthesizing diamonds and other superhard materials.

Illustrated in FIG. 1 is a die I which is braced with steel rings 2, and which has a site showing an erosion failure 3.

FIG. 2 presents the die of FIG. 1 after elimination of the erosion wear. The site of erosion failure 3 is filled with powdered refractory metal selected from the group consisting of nickel, iron, cobalt, manganese, molybdenum, titanium, tungsten. tantalum, chromium, niobium and rhenium, taken either singly or in various combinations thereof, and subjected to the effect of high pressure and temperature during the course of synthesizing artificial diammonds or other superhard materials. The powdered refractory metals are welded to the element being repaired under the high pressure and temperature conditions,

Illustrative examples of the inventive method being effected with various exemplary refractory materials under predetermined parameters of temperature and pressure are as follows:

EXAMPLE 1 The place of erosion wear of the die of a highpressure device was filled with a finely dispersed nickel powder whose volume was somewhat greater than that of the erosion wear formed.

Into the high-pressure device there was placed a container of lithographic stone repeating the shape of the high-pressure device die and containing a graphite cylindrical reaction vessel filled with a reaction mixture for the synthesis of diamonds consisting of a carboncontaining material and a catalyst metal in the volume proportion of 1:1.

Next the reaction mixture was subjected to the action of a pressure of 40 kbar and a temperature of 1 C during 15 minutes, after which the temperature and pressure were reduced to normal.

As a result of this process the volume of the highpressure device was restored to its initial one by hot pressing of the nickel in the zone of erosion wear.

EXAMPLE 2 The experiment was conducted in the same conditions as in example 1, except that the place of erosion wear was filled with an iron powder.

The result of the experiment was similar to that obtained in example 1 when using nickel.

EXAMPLE 3 EXAMPLE 4 The experiment was conducted similar to that described in example 1. except that the reaction mixture for the synthesis of diamonds was subjected to a pressure of 65 kbar and a temperature of l450C. and the place of erosion wear was filed with a finely dispersed tantalum powder. The result was similar to that obtained in example I.

EXAMPLE 5 The experiment was conducted similar to that described in example l. but at a pressure of 90 kbar and a temperature of I850C. while the place of erosion wear was filled with a mixture of tungsten and cobalt powders. As a result the working volume of the highpressure device was completely restored.

The method of the invention makes it possible to increase the service life of high pressure-high temperature devices and to restore the steady operating conditions of carrying out the process of synthesis of artificial diamonds and other superhard materials.

While there has been shown what is considered to be the preferred embodiment of the invention, it will be obvious that modifications may be made which come within the scope of the disclosure of the specification.

What we claim is:

1. A method of eliminating erosion failures on the surface of hard-alloy and steel components of devices operating under high pressure and at elevated temperature occuring at contact points between a reaction vessel and the surface of the die of said device. comprising the steps of l) filling the site of erosion failure with a powdered refractory metal selected from the group consisting of nickel, iron, cobalt, manganese, molybdenum. tungsten, chromium, titanium. tantalum, niobium, and rhenium taken singly or in various combinations thereof, (2) placing into said device, a container with a reaction vessel provided with non-metallic electrically conductive components at the point of contact between said vessel and the dies, said vessel containing the reaction mixture used for synthesis of diamonds or cubic boron nitride. and (3) subjecting said container containing the reaction mixture to the action of a pressure of at least 40 kbar and a temperature of at least 1 C for the time required for synthesis of diamonds or cubic boron nitride from said reaction mixture, so as to concurrently effect the process of synthesis and hot pressing of said powdered refractory metal.

* l l =l l= 

1. A METHOD OF ELIMINATING EROSION FAILURES ON THE SURFACE OF HARD-ALLOY AND STEEL COMPONENTS OF DEVICES OPERATING UNDER HIGH PRESSURE AND AT ELEVATED TEMPERATURE OCCURING AT CONTACT POINTS BETWEEN A REACTION VESSEL AND THE SURFACE OF THE DIE OF SAID DEVICE, COMPRISING THE STEPS OF (1) FILLING THE SITE OF EROSION FAILURE WITH A POWDERED REFRACTORY METAL SELECTED FROM THE GROUP CONSISTING OF NICKEL, IRON, COBALT, MANGANESE, MOLYBDENUM, TUNGSTEN, CHROMIUM, TITANIUM, TANTALUM, NIOBIUM, AND RHENIUM TAKEN SINGLY OR IN VARIOUS COMBINATIONS THEREOF, (2) PLACING INTO SAID DEVICE, A CONTAINER WITH A REACTION VESSEL PROVIDED WITH NON-METALLIC ELECTRICALLY CONDUCTIVE COMPONENTS AT THE POINT OF CONTACT BETWEEN SAID VESSEL AND THE DIES, SAID VESSEL CONTAINING THE REACTION MIXTURE USED FOR SYNTHESIS OF DIAMONDS OR CUBIC BORON NITRIDE, AND (3) SUBJECTING SAID CONTAINER CONTAINING THE REACTION MIXTURE TO THE ACTION OF A PRESSURE OF AT LEAST 40 KBAR AND A TEMPERATURE OF AT LEAST 1150*C FOR THE TIME REQUIRED FOR SYNTHESIS OF DIAMONDS OR CUBIC BORON NITRIDE FROM SAID REACTION MIXTURE, SO AS TO CONCURRENTLY EFFECT THE PROCESS OF SYNTHESIS AND HOT PRESSING OF SAID POWDERED REFRACTORY METAL. 